This revised ADAMHA Research Scientist Development Award application proposes studies of the ontogeny of motivation, reward and learning, and their physiological and neural substrates. The experiments exploit a developmental system of independent ingestive behavior in infant rats (described by my lab) and techniques for neural analysis recently adapted to infants. The proposed experiments are divided into two related research programs: (a) on ingestive development and (b) on early reward and learning. (a) Studies of ingestive development will assess sensory and physiological controls of ingestion in neonatal rats and describe how these controls develop, including assessing how such development is influenced by experience. Neural mechanisms underlying the developing ingestive system will be studied with brain transection techniques and deoxyglucose autoradiography. (b) Studies of early reward and learning will make use of ingestive rewards to describe and contrast the properties of basic forms of early learning as well as assess their long term effects. Neural mechanisms of early learning will be investigated using unilateral olfactory training techniques and deoxyglucose autoradiography. These experiments provide an ontogenetic analysis of a motivational system, one that can be followed from birth and manipulated in a controlled fashion, a system in which maturing neural systems can be related to changes in behavioral organization. This motivational system will be used to gain a better understanding of how specific early experiences influences the course of individual development, and determine how forms of early learning are represented in the brain. The award will contribute to my continued professional growth in areas of developmental analysis and expand my skill in neural and physiological analysis of behavioral mechanisms. Training plans are detailed in the proposal.